Field
Implementations described herein generally relate to the processing of low-k dielectric films. More specifically, implementations described herein relate to processes for sealing porous low-k dielectric films.
Description of the Related Art
As device scaling continues the dielectric constant (k) of dielectric films in semiconductor fabrication is continually decreasing. Minimizing integration damage on low dielectric constant (low-k) films is one factor that enables a continuing decrease in feature sizes. However, as feature sizes shrink, improvement in the resistive capacitance and reliability of dielectric films becomes a serious challenge.
Porous low-k dielectric films including, for example, carbon-doped oxides (CDO), suffer significant damages after going through back end of line (BEOL) integration due to the contamination in the exposed pores, which leads to larger resistive-capacitive (RC) delay. For example, metal and metal precursors tend to diffuse into the pores of the porous low-k dielectric films. In order to maintain the integrity of the porous low-k dielectric films and to minimize reliability degradation of the dielectric constant of the porous low-k dielectric films, porous low-k dielectric films are typically sealed prior to subsequent metallization processes. However, current sealing processes often lead to increased contact resistance.
Therefore, there is a need for methods of mitigating damage to the porous low-k dielectric films while also reducing contact resistance.